How to take over most of a continent

What I’m researching for the novel is: The kingdom of Caldwell is just one of 7 or 8 nations in a small area. They’ve had a war, lost most of their army, and now have a young and inexperienced king. Somehow, they end up being the main power in the region, conquering neighbouring kingdoms who refuse to surrender on their terms.

How does a small continent that is in the grip of depression, has been disarmed, and has a limitation on the size of their army turn into a superpower that nearly conquered a continent?

I’m not looking at specifics – somehow I don’t think Messerschmidts and Panzers have a place in a fantasy novel. But what were the underlying cirumstances that allowed it to happen?

Their enemies, fresh off their victory in WW1, continued to employ obsolete strategies that did not keep up with evolving technology. France, their biggest opponent, assumed that the Maginot Line which had served them well in WW1 would do the same in WW2. Germany, with tanks that didn’t require paved roads, simply came through the Ardennes.

Also, they were complacent after their victory. No one wanted another war, so they chose to appease Hitler instead. When he broke those terms by invading Czechoslovakia, Britain dismissed it as “a quarrel in a far-away country between people of whom we know nothing”. It wasn’t until he invaded Poland that Britain and France finally decided to take up arms!
(As an aside, WW1 started because it seems countries keep treaties, even when they know it will precipitate a large-scale war…)

Germany’s soldiers were fighting for a cause they truly believed in. They already felt unfairly done by with the Versailles Treaty enforced on them post-WW1, and just when they were recovering economically, along came the Great Depression. So when the Nazi party stepped up, gave them people to blame, and a firm and decisive course of action to take, people believed. They followed.
It helped that Goebbels was a master of propaganda, and controlled all media in the country.

Certain countries wished to remain neutral, and refused France passage when they wanted to mass their troops to face the Germans. By preventing France from taking the initiative, it helped to ensure their eventual fall – however inadvertent. In the end, those countries were conquered by Germany anyway!

There was conflict between the Allied forces – for example, the dispute between France and Britain (and Norway) over the course of action to be taken in Norway delayed them long enough for the Germans to come in and take the country.

Germany wasn’t alone – they had allies in the USSR, Italy and Japan. Japan was separated from Germany by the Asian continent, while Italy eventually became dependent on Germany and essentially became a subordinate state. Germany eventually turned on the USSR and invaded it – it was only the harsh winter and inability of the supply train to keep up that precipitated their defeat.

There’s many more reasons behind this, of course. Forced conscription into the German army and superior arms (complacency on the part of the Allies again!) being two major ones I didn’t list.

So, how does this apply to a fantasy setting? I’ll talk about this next week, so stay tuned.